The present invention relates generally to manufacturing operations, and more specifically to a system and apparatus for transport of semiconductor wafers in a semiconductor wafer fabrication facility.
Shuttle platforms are known which transport a payload, such as a semiconductor wafer pod, about a manufacturing facility. The payload is manipulated by various fabrication processes at different locations. The use of a shuttle platform expedites transport, provides precise placement, and minimizes the potential for operator error, such as a dropped payload. In manufacturing of delicate products, such as semiconductor wafers, operator error can result in substantial losses.
It is often advantageous to rotate a payload on a shuttle platform. Rotation serves to dispose the payload for optimal access by the various fabrication processes which manipulate the payload. A payload may be rotated to orient the payload for storage, to position the payload for access to a sealed environment, to allow for pickup by a robotic arm, and for other fabrication operations.
Rotation may be provided by direct activation from a drive source, such as a servo motor, or selectively provided through a rotary indexing mechanism. A separate drive source, however, must then be provided and powered, thereby increasing complexity and cost. Further, such a drive source must be calibrated to provide the precise positioning required. Finally, as a payload such as semiconductor wafers must not be subjected to bumping or jarring, rotation must not accelerate or decelerate too abruptly to avoid damaging the payload.
It would be beneficial, therefore, to provide a rotating payload platform which does not require a separate drive source, which provides a smooth motion profile through rotary acceleration and deceleration, and which minimizes calibration maintenance without sacrificing precision of rotation.